Bonus Track
Go to create new driver and enter the name CBLC. Begin a time trial on any course and when it comes on pause the game and click abort race. Now go to Corsica and select any track. It'll now open the bonus track up for you.

Extra Acceleration Power
Enter your name as LDN to get that extra boost.

Super Jump
To be able to be launched really high into the air when going over a jump, enter your name as "_FLY_" and you will be propelled high into the air.

Bonus tracks:
Enter one of the following driver names, begin a race, then quit. Start a new race, select a car, choose time trail mode, select "Corsica", and select any track to get to the corresponding bonus location.